As conventional opening/closing type communication terminals, for instance, an opening/closing type portable terminal apparatus is disclosed in JP-A-2001-251406, in which one casing is rotated along a direction perpendicular to an opening/closing direction. The opening/closing type portable terminal apparatus of this publication is arranged by employing an input unit for inputting information, a display unit for monitoring an operation condition and for displaying reception data, a control unit for controlling the input unit and the display unit, and a casing. It should be noted that the input unit owns a first input unit such as numeral keys, and a second input unit such as function keys. Also, the casing is arranged as follows. That is, this casing is divided into a first casing on which the second input unit is provided, and a second casing on which both the display unit and the second input unit are provided. The first casing is connected to the second casing by a hinge portion in a pivotable manner. Both the first casing and the second casing can be freely opened and closed, while the hinge portion is set as a rotation shaft.
As hinge apparatus for realize such a hinge portion, for example, one hinge apparatus is disclosed in JP-A-2000-240636. Referring now to FIG. 11, the hinge apparatus disclosed in JP-A-2000-240636 will be described. FIG. 11 is a plan view (A) and a side view (B) of the hinge apparatus disclosed in JP-A-2000-240636.
The hinge apparatus shown in FIG. 11 is arranged by employing the opening/closing shaft 202, the rotation shaft 203, the angle restricting piece 204, the restricting flange 205, and the rotation restricting portion 206. The opening/closing shaft 202 is pivotably supported by an opening/closing shaft supporting portion 201. The rotation shaft 203 rotatably penetrates through the opening/closing shaft 202 under perpendicular intersecting condition. The angle restricting piece 204 is provided in such a manner that this angular restricting piece 204 mutually abuts against both the opening/closing shaft supporting portion 201 and the opening/closing shaft 202. The restricting flange 205 is provided on the rotation shaft 202 under projected condition. The rotation restricting portion 206 is faced to the restriction flange 205 mounted on the opening/closing shaft supporting portion 201. In the case that this hinge apparatus is applied to the above-described opening/closing type communication terminal, a dimension of a hinge portion as the rotation shaft is determined by such a distance between a tip portion of the angle restricting piece 204 which is moved in connection with the rotation of the rotation shaft 203 and an axis center of the rotation shaft 203.
Also, as the conventional opening/closing type communication terminals, a portable telephone is disclosed in JP-A-6-311216. In the portable telephone disclosed in this publication, a first casing which is constituted by both a first front case and a first rear cover is pivotably connected to a second casing which is constituted by a second front case and a second rear cover by way of a hinge portion. Also, a first curved plane portion having an arc shape which is provided at an edge portion of the first front case is engaged with a second curved plane portion having an arc shape which is provided at an edge portion of the first rear cover so as to construct a first cavity portion having a substantially cylindrical shape which is internally communicated with the first casing at an edge portion of this first casing. Also, a second cavity portion having a substantially cylindrical shape is constituted at an edge portion of the second casing, which is internally communicated with this second casing. Then, the first cavity portion and the second cavity portion are arranged adjacent to each other in a coaxial manner. Also, a flexible printed board which connects an electric circuit employed in the first casing to an electric circuit employed in the second casing is wound and penetrated in a spiral shape along both an inner diameter of the first cavity portion and an inner diameter of the second cavity portion. Also, a cable which is present and is bridged over both the casings is elongated within an internal diameter of the flexible printed board which is wound in the spiral shape.
However, in the above-explained conventional communication terminal, even if the conventional hinge portion is mounted on such an apparatus as a portable telephone which is requested to be made compact so as to realize an opening/closing type portable telephone and the like, there is a problem that the apparatus becomes a large size due to the dimension of the hinge portion. Also, the dimension of the hinge portion is determined based upon the diameter of the opening/closing shaft, and the rotation radius of the angle restricting piece provided on the edge portion of the rotation shaft. In such an arrangement that the angle restricting piece is provided at the edge portion of the rotation shaft, the rotation radius is increased. There is such a problem that the size of the hinge portion becomes large.
Furthermore, since the opening/closing type portable telephone, or the like owns such a structure that bending stress and twist stress are produced on the flexible printed board in connection with the opening/closing operation thereof, there is a risk that a conductor portion (circuit pattern) of the flexible printed board is cut out.
FIG. 12 is a plan view for showing a flexible printed board which penetrates through the conventional hinge portion. As indicated in this drawing, the flexible printed board 300 is wound in a spiral shape within the hinge portion in order to be connected to connectors which are provided on a first casing (not shown) and a second casing (not shown) respectively. A twist angle “P” (see FIG. 12) of the flexible printed board which is wound in a right winding direction and directed from a lower side to an upper side is not changed even in such a case that the casings are folded. It should be noted that a two-dot and dash line indicates such a case that the casings have been folded.
However, since fixing positions (right/left directions) of both edges of the flexible printed board with respect to the first casing and the second casing are not changed, if the first casing and the second casing are folded from the opened condition, then the twist angle “P” is chanted into an approximately P/2. In other words, since the first casing and the second casing are folded, such a construction is made that both the bending stress and the twist angle are added to the flexible printed board.
Generally speaking, a flexible printed board owns a flexible characteristic, and thus, has a sufficiently strong construction with respect to bending stress. However, when various sorts of stress are applied in a composite manner to the flexible printed board, circuit disconnections and broken boards of the flexible printed board may be conducted. As a consequence, in the conventional opening/closing type portable telephones, if the opening/closing operations are repeatedly carried out, then the circuit disconnections and the broken boards of the flexible printed boars are conducted, which should be still improved.
Also, in the hinge apparatus (see FIG. 11) described in the above-explained JP-A-2000-240636, in such a case that an outer decoration cover for covering both the opening/closing shaft 202 and the rotation shaft 203 is provided, since the hinge apparatus owns such a structure that the opening/closing shaft 202 is pivotably moved within the opening/closing shaft supporting unit 201, the outer decoration cover cannot be made in close contact to the opening/closing shaft supporting portion 201 in order to avoid abrasion with respect to the opening/closing shaft supporting portion 201. As a result, a clearance is produced between the outer decoration cover and the opening/closing shaft 202. There is a risk that rain and the like are entered into this clearance, which may cause corrosion of appliances.
The present invention is made to solve the above-described conventional problems, and therefore, has an object to provide both a hinge apparatus in which a clearance between a rotating shaft and a cover member is small, and an opening/closing type communication terminal equipped with this hinge apparatus. Furthermore, the present invention owns another object to provide both a compact hinge apparatus in which a rotation radius of the rotating shaft is small, and also, an opening/closing type communication terminal equipped with this hinge apparatus.